Variability of urinary concentrations of glycol ether metabolites in pregnant women according to various sampling methods.

BACKGROUND

Although suspected to alter child development, exposure to glycol ethers (GEs) is widespread in the general population and remains insufficiently characterised, especially given their short half-lives.

OBJECTIVE

We investigated the variability of urinary concentrations of GE metabolites in pregnant women using different sampling methods.

METHODS

Thirty pregnant women were enroled by medical professional around Rennes, France. They completed questionnaires and underwent a repeated urine sampling protocol to collect all urine voids for one day and then two consecutive days, several weeks apart. We then measured the concentrations of nine GE metabolites in three pooled 24-h samples and three first morning void samples per woman, and all individual samples collected over two days (N = 530). We assessed the temporal variability of urinary GE metabolite concentrations for six sampling methods, calculating intraclass correlation coefficients (ICCs), using mixed-effects models with random effects for each day and participant.

RESULTS

The highest ICC ( > 0.75) was observed for sampling methods involving the collection of one or three random urine voids within a day for 2-methoxyproprionic acid (2-MPA), and for the first morning void for both 2-MPA and phenoxyacetic acid (PhAA). For other GE metabolites, none of the sampling methods seemed to offer good enough reproducibility, with ICC < 0.63.

SIGNIFICANCE: Among the methods assessed, FMV seemed to provide the best balance between reproducibility for PhAA and 2-MPA. For other metabolites, no sampling method seemed to provide sufficient reproducibility.

IMPACT: Perinatal health concerns have been reported in association with exposure to glycol ethers (GEs). Reproducible methods for measuring GE exposure in pregnant women are therefore required. Metabolite-specific sampling strategies may be appropriate to investigate exposure-response associations.